Botulinum toxin is a specific neurotoxic protein that blocks the release of the neurotransmitter acetylcholine. Botulinum toxin types A and B, consists of three structural domains responsible for the three processes leading to inhibition of acetylcholine release. We want to determine the three dimensional structures of Botulinum toxin and of a carbohydrate complex (ganglioside GT1B) to atomic resolution and obtain a native data set for a BTA or BTB carbohydrate complex.